The production of aroma compounds represents an important tool in the production of natural flavors for food and beverage industries. E. Albertazzi, et al., Biotech. Lett. 16, 491-6 (1994). One of the most commonly used aroma compounds is phenethyl alcohol. Phenethyl alcohol (e.g., phenethanol, 2-phenylethanol, or benzeneethanol) is naturally present in many essential oils, and has a rose-like/honey floral odor. Phenethyl alcohol is chemically synthesized or extracted in commercial applications as a flavoring or fragrance for consumer goods, such as perfumes and food.
As a flavorant, phenethyl alcohol is useful in producing a broad range of desirable flavors, especially imitation butter, strawberry, raspberry, caramel, honey, melon and other fruit complexes. S. Arctander, Perfume and Flavor Chemicals Vol. 2, 2513 (1969). Phenethyl alcohol is also one of the most widely used of all perfume chemicals, and is particularly desired as a component in perfumes that are characterized as floral, balsamic, Oriental, mossy, herbaceous, or "modern aldehydic." Id. In addition to providing its own distinctive aroma, phenethyl alcohol may be also blended with other aroma compounds (e.g., rose alcohols, lily alcohols, and muguet alcohols) to produce floral scents as well as lime and spice blends. Id. Additionally, phenethyl alcohol is used as an antimicrobial and as a solution preservative. See R. M. E. Richards and R. J. McBride, J. Pharm. Pharmac. 24, 145-148 (1972); ibid, 21, 681-686 (1969).
Phenethyl alcohol occurs naturally in alcoholic fermented foods in amounts of 10-100 ppm. M. E. Kieser, et al., Nature 204, 887 (1964). This amount, while affecting the quality of alcoholic beverages, is not sufficient as a source for the large-scale production of the natural aroma component. It is therefore of interest to develop methods of producing and isolating phenethyl alcohol in large amounts, and of high purity.
Phenethyl alcohol may be produced by fermenting solutions containing L-phenylalanine under appropriate fermentation conditions. See Albertazzi, et al., supra at 492. Conventional methods of isolating phenethyl alcohol from such fermented solutions generally involve liquid-liquid solvent extraction utilizing high volumes of organic solvents such as butanol. One disadvantage of the solvent extraction technique is the formation of emulsions during extraction, requiring the use of excess solvent and longer times for phase separation. Additionally, the solvent extraction techniques are often cumbersome, and do not provide an optimal yield of final product.
It would be highly desirable to provide a practical and less hazardous method of isolating phenethyl alcohol whereby a high yield of final product is afforded, and the need for large volumes of organic solvent is obviated.